Treatment of superficial wounds such as Stage I-IV pressure ulcers, stasis ulcers, first and second degree burns, cuts, abrasions and other minor irritations of the skin present several inconveniences for both health care personnel and patients. Such wounds are highly susceptible to bacterial infections and thus maintenance of cleanliness of the healing surface is desirable. Additionally, foreign particles may become incorporated into the wound surface as it heals over. Response to this problem has lead to wound dressings covering the injured area as it heals.
Conventional wound dressings usually involve a fabric or felt of absorptive material such as gauze in direct contact with the wound. Such conventional dressings are normally covered in order to avoid or reduce bacterial contamination but the dressing itself is not efficient in this respect. They do have the general advantage of absorbing exudate from the wound, but on the other hand, tend to stick to the wound surface thus inhibiting healing. Furthermore, removal of the dressing is commonly painful and disruptive where such adherence has occurred. Thus, benefits of covering the wound are accompanied by a host of other problems as the wound begins to scab over. Additionally scabbing often entraps foreign material hindering healing and will limit movement of the patient when the injury occurs in an area of the skin which is stretched in response to joint movement, such as the knee. Ideal healing occurs from the inside out.
A recent advancement has been the use and development of hydrogel polymer wound dressings, including polysaccarides, proteins and polypeptides. These gels prevent drying and eventually scabbing of the sore due to a markably strong bonding of water with the polymer molecule. A particular feature of these hydrogel dressings is that they resist entry of bacteria and thus maintain cleanliness of the healing surface, whereas fabric coverings being porous tend to permit bacterial invasion. The gel form of the wound dressing is beneficial in that it is easily deliverable from soft tubes. However even with hydrogels there is always the conflict between desirable properties for would dressing and packaging, i.e. between a gel which is easy to package but too soft and flowable which will simply run out of the wound and not adequately adhere, and on the other hand the more viscous products which are difficult to package and dispense from containers, and too sticky causing tissue damage or which hinder wound cleansing.
Current wound dressings in use include petroleum jellies. These dressings however can form a dry film leading to the problems earlier discussed as to sticking to the gauze bandage and tearing of the delicate regenerated skin upon removal. Another conventional dressing includes paraffins and petroleums. These however are not water soluble and present difficulties in removal during wound cleansing.
The advancements in the area of water hydrated compounds for use as wound dressings has also presented difficulties. One such hydrophilic material which would seem promising is glycerin; however, use of glycerin alone is not workable in that it is not viscous enough. When placed on a wound, glycerin, particularly after water absorption, will simply fall out of the wound. Other such gels as disclosed in Smith et al U.S. Pat. No. 4,889,530 tend to be viscous enough to adhere to the wound but go too far in the other direction in that they posses thickening properties when applied to the wound such that upon removal during cleansing they often tear delicate regenerated tissue.
A common problem even for hydrogels, is that the product must be able to adhere to both moist and dry skin and yet be easily removable during wound washing. If one emphasizes water solubility in formulation to allow easy washing removal, wound adherence is compromised along with the desirable protectant function from contamination. Moreover increased water solubility often means "drying out" which creates further problems in wound healing.
It is an object of the present invention to provide a hydrogel polymer based wound dressing of a viscosity such that it will adhere to the wound to provide moistness and yet is easily water soluble and non thickening such that it may be removed without tearing delicate regenerated tissue.
Yet another object of the invention is to provide a clear viscous hydrogel which will protect the wound bed from foreign contaminants and bacteria to enhance the natural healing process.
Yet another object of the invention is to provide a wound dressing which may be easily dispensed in gel form from a soft tube container.
A still further object of the invention is to provide a wound dressing which will promote healing of the wound from the inside out by keeping the wound moist to prevent drying and scab formation as well as effective protection from infection.
Further objects of the invention will come apparent in the description of the invention which follows.